PromptTrackCountingComputer.h

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#ifndef ImpactParameter_PromptTrackCountingComputer_h
#define ImpactParameter_PromptTrackCountingComputer_h
 
// This returns a discriminator equal to the number of prompt tracks in the jet
// It is intended for exotica physics, not b tagging.
// It closely resembles the TrackCountingComputer, but with a different discrinator definition and slightly different cuts.
// Author: Ian Tomalin
 
#include "DataFormats/TrackReco/interface/Track.h"
#include "DataFormats/VertexReco/interface/Vertex.h"
#include "DataFormats/BTauReco/interface/TrackCountingTagInfo.h"
#include "DataFormats/BTauReco/interface/TrackIPTagInfo.h"
#include "Math/GenVector/VectorUtil.h"
#include "RecoBTau/JetTagComputer/interface/JetTagComputer.h"
 
class PromptTrackCountingComputer : public JetTagComputer {
public:
  using Tokens = void;
 
  PromptTrackCountingComputer(const edm::ParameterSet& parameters) {
    m_nthTrack = parameters.getParameter<int>("nthTrack");
    m_ipType = parameters.getParameter<int>("impactParameterType");
    // Maximum and minimum allowed deltaR respectively.
    m_deltaR = parameters.getParameter<double>("deltaR");
    m_deltaRmin = parameters.getParameter<double>("deltaRmin");
    maxImpactParameter = parameters.getParameter<double>("maxImpactParameter");
    maxImpactParameterSig = parameters.getParameter<double>("maxImpactParameterSig");
    m_cutMaxDecayLen = parameters.getParameter<double>("maximumDecayLength");          //used
    m_cutMaxDistToAxis = parameters.getParameter<double>("maximumDistanceToJetAxis");  //used
    //
    // access track quality class; "any" takes everything
    //
    std::string trackQualityType = parameters.getParameter<std::string>("trackQualityClass");  //used
    m_trackQuality = reco::TrackBase::qualityByName(trackQualityType);
    m_useAllQualities = false;
    if (trackQualityType == "any" || trackQualityType == "Any" || trackQualityType == "ANY")
      m_useAllQualities = true;
 
    uses("ipTagInfos");
  }
 
  float discriminator(const TagInfoHelper& ti) const override {
    const reco::TrackIPTagInfo& tkip = ti.get<reco::TrackIPTagInfo>();
    std::multiset<float> significances = orderedSignificances(tkip);
    std::multiset<float>::iterator sig;
    unsigned int nPromptTrk = 0;
    for (sig = significances.begin(); sig != significances.end(); sig++) {
      if (fabs(*sig) < maxImpactParameterSig)
        nPromptTrk++;
      //       edm::LogDebug("") << "Track "<< nPromptTrk << " sig=" << *sig;
    }
    return double(nPromptTrk);
  }
 
protected:
  std::multiset<float> orderedSignificances(const reco::TrackIPTagInfo& tkip) const {
    const std::vector<reco::btag::TrackIPData>& impactParameters((tkip.impactParameterData()));
    const edm::RefVector<reco::TrackCollection>& tracks(tkip.selectedTracks());
    std::multiset<float> significances;
    int i = 0;
    if (tkip.primaryVertex().isNull()) {
      return std::multiset<float>();
    }
 
    GlobalPoint pv(tkip.primaryVertex()->position().x(),
                   tkip.primaryVertex()->position().y(),
                   tkip.primaryVertex()->position().z());
 
    for (std::vector<reco::btag::TrackIPData>::const_iterator it = impactParameters.begin();
         it != impactParameters.end();
         ++it, i++) {
      if (fabs(impactParameters[i].distanceToJetAxis.value()) < m_cutMaxDistToAxis &&  // distance to JetAxis
          (impactParameters[i].closestToJetAxis - pv).mag() < m_cutMaxDecayLen &&      // max decay len
          (m_useAllQualities == true || (*tracks[i]).quality(m_trackQuality))          // use selected track qualities
      ) {
        if ((m_deltaR <= 0 ||
             ROOT::Math::VectorUtil::DeltaR((*tkip.jet()).p4().Vect(), (*tracks[i]).momentum()) < m_deltaR) &&
            (m_deltaRmin <= 0 ||
             ROOT::Math::VectorUtil::DeltaR((*tkip.jet()).p4().Vect(), (*tracks[i]).momentum()) > m_deltaRmin)) {
          if (fabs(((m_ipType == 0) ? it->ip3d : it->ip2d).value()) < maxImpactParameter) {
            significances.insert(((m_ipType == 0) ? it->ip3d : it->ip2d).significance());
          }
        }
      }
    }
 
    return significances;
  }
 
  int m_nthTrack;
  int m_ipType;
  double m_deltaR;
  double m_deltaRmin;
  double maxImpactParameter;
  double maxImpactParameterSig;
  double m_cutMaxDecayLen;
  double m_cutMaxDistToAxis;
  reco::TrackBase::TrackQuality m_trackQuality;
  bool m_useAllQualities;
};
 
#endif  // ImpactParameter_PromptTrackCountingComputer_h